Solid freeform fabrication is a process for manufacturing three-dimensional objects. Typical objects that may be manufactured using solid free form fabrication include, for example, prototype parts, production parts, models, and working tools. Solid freeform fabrication is an additive process in which a desired object is described by electronic data and automatically built from base materials. Selective deposition is one common method of solid freeform fabrication.
Typical selective deposition methods include using a dispensing mechanism to deposit, at particular locations, individual drops of material known as voxels. A selective deposition system typically incorporates two different solidifiable materials. A first material is used to fabricate the actual desired three-dimensional object, and a second material is a sacrificial material used to build a support structure for the first material.
Several variations of selective deposition exist. One variation includes depositing two materials (one for support and one for the desired three-dimensional object) that solidify upon application. This variation of the selective deposition method requires object build material to be dispensed at each voxel location corresponding to a part of the desired three-dimensional object. Accordingly, physical defects result when the dispensing mechanism has missing or misdirected nozzles.
Another common variation of selective deposition includes depositing at least two materials (support and object) that both remain in liquid form until they are exposed to radiation (e.g. ultraviolet “UV” light). This second variation also presents a number of issues. First, interfaces between support and build materials are not well defined as the liquids tend to mix. This mixing between the two materials results in rough object surfaces. Second, the support material is usually solidified and cross-linked making it difficult to remove from the desired three-dimensional object without damaging the desired object. Further, as with the first variation, the build material must be dispensed at each voxel location of the desired object, slowing the fabrication process.